The invention relates to a system and method for making frozen beverages and, more specifically, to a system and method for making reduced-calorie (“light”) and diet frozen beverages.
Full-calorie frozen beverages are known in the art and have been produced for years. Frozen beverages are produced via devices that freeze a mixture of ingredients including syrup, water, and optionally, carbon dioxide in a mixing chamber. The mixture freezes on the inner surface of the mixing chamber, which is surrounded by a helical coil through which a refrigerant passes. A rotating shaft is disposed inside the chamber, which has a plurality of outwardly projecting blades that scrape the frozen mixture off the inside wall of the mixing chamber. Once the beverage is in the desired frozen state, the product is dispensed from the chamber through a product valve.
Current frozen beverage products are generally limited to full-calorie frozen beverages. Caloric products contain common sugars, such as sucrose or high fructose corn syrup (“HFCS”), which are used as sweeteners. These sugars play an important part in the freezing point depression of frozen beverages. Under normal operating conditions of frozen beverage machines, the addition of caloric sweeteners depresses the freezing point of the product, making them dispensable in a slush-like state. By contrast, a diet beverage—or non-caloric beverage—contains no common sugars such as sucrose or corn syrup, and thus lacks a freezing point depressant. Without this modified freezing point, diet syrup freezes into blocks of ice in a conventional frozen beverage machine.
The degree of sweetness in a beverage is generally listed, or measured, by a brix value. Brix value is generally defined as the percent of soluble solids made up of sugars. A blend having a high brix value generally tends to be sweeter and may be difficult to freeze. On the other hand, a beverage having a low brix value, for example, less than 10, may be too icy when frozen. Since the brix value of diet or low-calorie beverages typically ranges from about 3.5 to about 5.0, commercial success for dispensing diet or low-calorie frozen beverages has been minimal.
In some conventional frozen beverage machines for diet, low-calorie, and reduced-calorie beverages, the freezing point of the syrup is depressed by the addition of sugars and HFCS. This solution, however, may raise the brix value of the beverage beyond the permissible limit for low-calorie, diet, and reduced-calorie products. A frozen beverage machine capable of producing a diet or low-calorie frozen beverage, which has a brix value of less than about 7.5, while having the consistency of a full-calorie frozen beverage (i.e., without large pieces of ice) is desired.
In some beverage machines, the temperature and viscosity of the ingredients within the mixing chamber are maintained by a control system that controls the refrigeration system. Product quality is controlled through the balance of ingredients as well as pressures and temperatures within the chamber.
The present invention may overcome one or more of the problems associated with the production of diet frozen beverages through the use of a refrigeration configuration and/or one or more control schemes that allow the available refrigeration capacity to adjust for dynamic evaporating loads, while maintaining uniform saturation and/or flooding of the evaporator at a controlled desired temperature. Thus, the present invention may enable diet or light-product to freeze uniformly and dispense consistently from initial freeze through extended low-draw conditions. Additionally, the present invention may enable a higher level of control with respect to ice crystal formation, which may enable the equipment to produce products having a consistency that is a closer representation of HFCS-based products.